Added support for DECSCUSR sequences (#941)

* Falling back to legacy cursor for higher values of CursorStyle

Co-Authored-By: Michael Niksa <miniksa@microsoft.com>

src/cascadia/TerminalControl/TermControl.cpp

@@ -910,6 +910,10 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
     void TermControl::_BlinkCursor(Windows::Foundation::IInspectable const& /* sender */,
                                    Windows::Foundation::IInspectable const& /* e */)
     {
+        if (!_terminal->IsCursorBlinkingAllowed() && _terminal->IsCursorVisible())
+        {
+            return;
+        }
         _terminal->SetCursorVisible(!_terminal->IsCursorVisible());
     }
 

src/cascadia/TerminalCore/ITerminalApi.hpp

@@ -1,7 +1,9 @@
 // Copyright (c) Microsoft Corporation.
 // Licensed under the MIT license.
-
 #pragma once
+
+#include "../../terminal/adapter/DispatchTypes.hpp"
+
 namespace Microsoft::Terminal::Core
 {
     class ITerminalApi
@@ -27,5 +29,7 @@ namespace Microsoft::Terminal::Core
         virtual bool SetWindowTitle(std::wstring_view title) = 0;
 
         virtual bool SetColorTableEntry(const size_t tableIndex, const DWORD dwColor) = 0;
+
+        virtual bool SetCursorStyle(const ::Microsoft::Console::VirtualTerminal::DispatchTypes::CursorStyle cursorStyle) = 0;
     };
 }

src/cascadia/TerminalCore/Terminal.cpp

@@ -605,3 +605,9 @@ void Terminal::SetCursorVisible(const bool isVisible) noexcept
     auto& cursor = _buffer->GetCursor();
     cursor.SetIsVisible(isVisible);
 }
+
+bool Terminal::IsCursorBlinkingAllowed() const noexcept
+{
+    const auto& cursor = _buffer->GetCursor();
+    return cursor.IsBlinkingAllowed();
+}

src/cascadia/TerminalCore/Terminal.hpp

@@ -71,6 +71,7 @@ public:
     bool EraseCharacters(const unsigned int numChars) override;
     bool SetWindowTitle(std::wstring_view title) override;
     bool SetColorTableEntry(const size_t tableIndex, const DWORD dwColor) override;
+    bool SetCursorStyle(const ::Microsoft::Console::VirtualTerminal::DispatchTypes::CursorStyle cursorStyle) override;
     #pragma endregion
 
     #pragma region ITerminalInput
@@ -114,6 +115,7 @@ public:
     void SetScrollPositionChangedCallback(std::function<void(const int, const int, const int)> pfn) noexcept;
 
     void SetCursorVisible(const bool isVisible) noexcept;
+    bool IsCursorBlinkingAllowed() const noexcept;
 
     #pragma region TextSelection
     const bool IsSelectionActive() const noexcept;

src/cascadia/TerminalCore/TerminalApi.cpp

@@ -169,3 +169,53 @@ bool Terminal::SetColorTableEntry(const size_t tableIndex, const DWORD dwColor)
     _buffer->GetRenderTarget().TriggerRedrawAll();
     return true;
 }
+
+// Method Description:
+// - Sets the cursor style to the given style.
+// Arguments:
+// - cursorStyle: the style to be set for the cursor
+// Return Value:
+// - true iff we successfully set the cursor style
+bool Terminal::SetCursorStyle(const DispatchTypes::CursorStyle cursorStyle)
+{
+    CursorType finalCursorType;
+    bool fShouldBlink;
+
+    switch (cursorStyle)
+    {
+    case DispatchTypes::CursorStyle::BlinkingBlockDefault:
+        [[fallthrough]];
+    case DispatchTypes::CursorStyle::BlinkingBlock:
+        finalCursorType = CursorType::FullBox;
+        fShouldBlink = true;
+        break;
+    case DispatchTypes::CursorStyle::SteadyBlock:
+        finalCursorType = CursorType::FullBox;
+        fShouldBlink = false;
+        break;
+    case DispatchTypes::CursorStyle::BlinkingUnderline:
+        finalCursorType = CursorType::Underscore;
+        fShouldBlink = true;
+        break;
+    case DispatchTypes::CursorStyle::SteadyUnderline:
+        finalCursorType = CursorType::Underscore;
+        fShouldBlink = false;
+        break;
+    case DispatchTypes::CursorStyle::BlinkingBar:
+        finalCursorType = CursorType::VerticalBar;
+        fShouldBlink = true;
+        break;
+    case DispatchTypes::CursorStyle::SteadyBar:
+        finalCursorType = CursorType::VerticalBar;
+        fShouldBlink = false;
+        break;
+    default:
+        finalCursorType = CursorType::Legacy;
+        fShouldBlink = false;
+    }
+
+    _buffer->GetCursor().SetType(finalCursorType);
+    _buffer->GetCursor().SetBlinkingAllowed(fShouldBlink);
+
+    return true;
+}

src/cascadia/TerminalCore/TerminalDispatch.cpp

@@ -70,3 +70,8 @@ bool TerminalDispatch::SetColorTableEntry(const size_t tableIndex,
 {
     return _terminalApi.SetColorTableEntry(tableIndex, dwColor);
 }
+
+bool TerminalDispatch::SetCursorStyle(const DispatchTypes::CursorStyle cursorStyle)
+{
+    return _terminalApi.SetCursorStyle(cursorStyle);
+}

src/cascadia/TerminalCore/TerminalDispatch.hpp

@@ -25,6 +25,7 @@ public:
     bool SetWindowTitle(std::wstring_view title) override;
 
     bool SetColorTableEntry(const size_t tableIndex, const DWORD dwColor) override;
+    bool SetCursorStyle(const ::Microsoft::Console::VirtualTerminal::DispatchTypes::CursorStyle cursorStyle) override;
 
 private:
     ::Microsoft::Terminal::Core::ITerminalApi& _terminalApi;